LEASES - Additional Information (Detail) (USD $)	1 Months Ended		3 Months Ended			9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended			9 Months Ended		9 Months Ended
	Sep. 30, 2012 Property State	May 31, 2012	Sep. 30, 2012 Property State	Dec. 31, 2011	Sep. 30, 2011	Sep. 30, 2012 Property State	Sep. 30, 2011	Sep. 30, 2012 Marketing Leases [Member]	Sep. 30, 2011 Marketing Leases [Member]	Sep. 30, 2012 Marketing Leases [Member]	Sep. 30, 2011 Marketing Leases [Member]	Jun. 30, 2012 Allowance for doubtful accounts [Member]	Mar. 31, 2012 Allowance for doubtful accounts [Member]	Dec. 31, 2011 Allowance for doubtful accounts [Member]	Sep. 30, 2012 Allowance for doubtful accounts [Member]	Sep. 30, 2012 USTs [Member]	Sep. 30, 2012 Minimum [Member]	Sep. 30, 2012 Maximum [Member]
Leases [Line Items]
Number of properties leased for other retail purposes	20		20			20
Number of properties marketed for sale and which have temporary occupancies						55
Number of properties	1,110		1,110			1,110
Number of states in which our properties are located	21		21			21
Number of properties previously leased to GPMI	760		760			760
Bad debt reserve												$ 16,221,000	$ 16,221,000	$ 8,802,000	$ 567,000
Reduction to our bad debt reserves for Marketing															24,456,000
Number of new triple net leases we've entered into						6
Number of leased properties with new tenants						282
License agreements with occupants properties including Marketing's former sub-tenants						330
Properties which have had their underground storage tanks removed						55
Properties previously subject to the Master Lease that are vacant and marked for sale						80
Unitary triple-net lease agreements initial terms																	15 years
Unitary triple-net lease agreements successive terms																		20 years
Amount of asset retirement obligations removed from the balance sheet			6,875,000			6,875,000
Net asset costs related to USTs removed from the balance Sheet																6,203,000
Deferred rental revenue	672,000		672,000			672,000
Future contractual minimum annual rentals receivable one year	7,691,000		7,691,000			7,691,000
Future contractual minimum annual rentals receivable two year	13,694,000		13,694,000			13,694,000
Future contractual minimum annual rentals receivable three year	14,568,000		14,568,000			14,568,000
Future contractual minimum annual rentals receivable four year	14,960,000		14,960,000			14,960,000
Future contractual minimum annual rentals receivable five year	15,106,000		15,106,000			15,106,000
Future contractual minimum annual rentals receivable thereafter	162,858,000		162,858,000			162,858,000
Revenues from rental properties included in continuing operations			22,386,000			76,332,000
Revenues due or received from Marketing under the Master Lease			102,000			20,535,000
Revenues related to properties repositioned	51,800,000	21,408,000
Real estate taxes paid that were reimbursed by tenant			1,928,000		1,542,000	8,398,000	3,104,000
Revenues realized under interim fuel supply agreements						1,003,000
Real estate taxes paid related to the portfolio previously leased to Marketing								1,928,000	1,542,000	8,398,000	3,104,000
Increase rental revenue			1,459,000		253,000	2,994,000	1,338,000
Gross deferred receivable attributable to the Master Lease with Marketing that was fully reserved				25,630,000
Non-cash allowances for deferred rental revenue				8,715,000	11,043,000
Investment in direct financing lease	92,110,000		92,110,000			92,110,000
Investments in direct financing lease, minimum lease payments receivable	206,597,000		206,597,000			206,597,000
Investment in direct financing lease, unguaranteed estimated residual value	11,991,000		11,991,000			11,991,000
Investment in direct financing lease, deferred income	$ 126,478,000		$ 126,478,000			$ 126,478,000